Re: Non-booting current Linus' tree

[Thomas Gleixner <tglx@linutronix.de>]

On Fri, 3 Jul 2015, Jan Kara wrote:
>   so I was wondering why I cannot boot current Linus' tree in my kvm
> instance. The boot dies after writing "Booting the kernel" message. After
> some bisection I have identified the culprit is in commit
> 91a8c2a5b43fc4be4adb4bda50cd331697e289e0 (x86/fpu: Clean up and fix MXCSR
> handling). After applying that commit I start to get oopses like:

At least you get oopses. My hardware simply refused to spit out
anything useful and my bisect just ended up at the same commit.
 
> And indeed the oops happens at:
>   2b:*	0f ae 85 00 fe ff ff 	fxsave -0x200(%rbp)		<--
> trapping instruction
> 
> Because the address isn't 32-byte aligned (which I assume is the
> requirement from looking into the code). So clearly my gcc messed up and
> miscompiled the thing by ignoring the alignment attribute. Now my build
> host is rather old installation (SLES 11 SP3) running gcc 4.3.4 but there
> are quite a few installations of it still running. So do we care or should
> I just upgrade the build host?

My gcc is old as well. 4.3.0-8. 

Thanks,

	tglx